The present invention relates to the field of electronic devices which are equipped with touch screen displays. More specifically, the present invention relates to activating an electronic touch screen device from a quiescent low power state.
There are many different electronic devices available to the general public which offer a wide variety of useful functions to their operators. Several of these electronic devices are equipped with a touch screen display along with a hand-held stylus. Typically, instead of interfacing with these electronic devices through a common keyboard, the operator can utilize the hand-held stylus (or their finger) in conjunction with the touch screen display. For instance, the operator is able to cause the electronic touch screen device to perform specific desired functions by touching the stylus or their finger to its touch screen display. Furthermore, the operator is able to input information into the electronic touch screen device by advantageously writing with the stylus across its touch screen display.
There are many different examples of these electronic touch screen devices such as computer navigation devices installed within automobiles, portable (laptop) computer systems, automated teller machines (ATMs) of commercial banks, point of sale machines located within commercial stores and restaurants, and desktop computer systems. One of the familiar types of electronic touch screen devices is referred to as a personal digital assistant, commonly referred to as a PDA. Currently, one of the well known brands of personal digital assistant is sold under the name of Palm Pilot(copyright) and is available from 3Com Corporation of Santa Clara, Calif. The personal digital assistant is a battery powered hand-held touch screen device that is used as an electronic organizer that has the capability to store a wide range of information which can include daily appointments, numerous telephone numbers of business and personal acquaintances, and various other information.
Since personal digital assistants and other electronic touch screen devices are often battery powered, it is very important to prolong the life of their batteries as much as possible. Furthermore, the need also arises to decrease the amount of power consumed by electronic touch screen devices which are powered by a typical wall outlet. One prior art method for prolonging battery life or decreasing power consumption is to provide a button which the operator can push, thereby forcing the touch screen device into its quiescent low power state-while it is not being actively used. Once the touch screen device is within the quiescent low power state, its power consumption is maintained at some minimum level. Another prior art method for decreasing power consumption or prolonging battery life is to utilize some type of internal timer to automatically force the touch screen device into its quiescent low power state after a specific amount of non-use time has elapsed.
Within the prior art, if the operator desires to restore the touch screen device to its normal operating mode from its quiescent low power state, the operator needs to push a specific button on the touch screen device. Even though using the button activates the touch screen device from its quiescent low power state, it is not a very convenient way to activate this wake up function. Furthermore, it is not intuitive to the average operator of a touch screen device what specific action is required to restore the device to its normal active operating mode.
Therefore, it would be advantageous to provide a system which activates an electronic touch screen device without requiring the user to manipulate specific buttons. A further need exists for a system which activates an electronic touch screen device without requiring the user to have extensive knowledge of the operation requirements of the electronic touch screen device. The present invention provides these advantages.
The present invention includes a method and system for detecting a power management system resume event from a stylus and touch screen. When an electronic device equipped with a touch screen display is within its quiescent low power state, the present invention enables an operator to activate it by touching a stylus or their finger to its touch screen display. Specifically, an embodiment in accordance with the present invention includes a comparator installed within an electronic touch screen device. While the electronic touch screen device is within its quiescent low power state, the comparator determines whether the touch screen display has been touched by comparing an output voltage signal transmitted by the touch screen display with a reference voltage signal. When the touch screen display is touched, the voltage of the output voltage signal becomes greater than the voltage of the reference voltage signal, causing the comparator to transmit a resume event signal. The resume event signal causes the electronic touch screen device to wake up from its quiescent low power state.
Another embodiment of the present invention is a circuit that activates an electronic touch screen device from its quiescent low power state. The circuit in accordance with the present invention comprises a touch screen display which is adapted to transmit a first signal when it has been touched. The circuit also includes a reference source adapted to transmit a reference signal. Furthermore, a comparator circuit is coupled to receive the first signal from the touch screen display and the reference signal from the reference source. The comparator circuit is adapted to determine whether the touch screen display has been touched by comparing the first signal with the reference signal. The comparator circuit subsequently outputs a second signal in response to the touch screen display being touched which activates the electronic touch screen device from its quiescent low power state.
These and other advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the drawing figures.